checkName=STRING, -- Use STRING as QNAME in the health-check query, default: "a.root-servers.net."
checkType=STRING, -- Use STRING as QTYPE in the health-check query, default: "A"
setCD=BOOL, -- Set the CD (Checking Disabled) flag in the health-check query, default: false
- maxCheckFailures=NUM, -- Allow NUM check failures before declaring the backend down, default: false
+ maxCheckFailures=NUM, -- Allow NUM check failures before declaring the backend down, default: 1
mustResolve=BOOL, -- Set to true when the health check MUST return a NOERROR RCODE and an answer
useClientSubnet=BOOL, -- Add the client's IP address in the EDNS Client Subnet option when forwarding the query to this backend
source=STRING -- The source address or interface to use for queries to this backend, by default this is left to the kernel's address selection